Package Instance

Prevent user enumeration using Guard or the new Authenticator-based Security
Description
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The ability to enumerate users was possible without relevant permissions due to different exception messages depending on whether the user existed or not. It was also possible to enumerate users by using a timing attack, by comparing time elapsed when authenticating an existing user and authenticating a non-existing user.

Resolution
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We now ensure that 403s are returned whether the user exists or not if the password is invalid or if the user does not exist.

The patch for this issue is available [here](https://github.com/symfony/symfony/commit/2a581d22cc621b33d5464ed65c4bc2057f72f011) for branch 3.4.

Credits
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I would like to thank James Isaac and Mathias Brodala for reporting the issue and Robin Chalas for fixing the issue.

Firewall configured with unanimous strategy was not actually unanimous in Symfony
Description
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On Symfony before 4.4.0, when a `Firewall` checks an access control rule (using the unanimous strategy), it iterates over all rule attributes and grant access only if *all* calls to the `accessDecisionManager` decide to grant access.

As of Symfony 4.4.0, a bug was introduced that prevents the check of attributes as soon as `accessDecisionManager` decide to grant access on one attribute.

Resolution
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The `accessDecisionManager` is now called with all attributes at once, allowing the unanimous strategy being applied on each attribute. 

The patch for this issue is available [here](https://github.com/symfony/symfony/commit/c935e4a3fba6cc2ab463a6ca382858068d63cebf) for the 4.4 branch.

Credits
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I would like to thank Antonio J. García Lagar for reporting & Robin Chalas for fixing the issue.

RCE in Symfony
Description
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The `CachingHttpClient` class from the HttpClient Symfony component relies on the `HttpCache` class to handle requests. `HttpCache` uses internal headers like `X-Body-Eval` and `X-Body-File` to control the restoration of cached responses. The class was initially written with surrogate caching and ESI support in mind (all HTTP calls come from a trusted backend in that scenario). But when used by `CachingHttpClient` and if an attacker can control the response for a request being made by the `CachingHttpClient`, remote code execution is possible.

Resolution
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HTTP headers designed for internal use in `HttpCache` are now stripped from remote responses before being passed to `HttpCache`.

The patch for this issue is available [here](https://github.com/symfony/symfony/commit/d9910e0b33a2e0f993abff41c6fbc86951b66d78) for the 4.4 branch.

Credits
-------

I would like to thank Matthias Pigulla (webfactory GmbH) for reporting and fixing the issue.